package cc.openhome;

import java.util.Scanner;

public class Average {
    public static void main(String[] args) {
	Scanner console = new Scanner(System.in);
	double sum = 0;
	int count = 0;
	while(true) {
	    int number =console.nextInt();
	    if(0 == number) {
		break;
	    }
	    sum += number;
	    count++;
	}
	System.out.printf("平均 %.2f%n", sum / count);
    }
}
